body {
    font-family: sans-serif;
    margin: 40px;
    background: #f5f5f5;
}

header {
    background: #fff;
    padding: 20px;
    border-left: 5px solid #0078ff;
    margin-bottom: 30px;
}

h1 {
    margin: 0;
}

button {
    padding: 10px 20px;
    background: #0078ff;
    color: #fff;
    border: none;
    cursor: pointer;
}

button:hover {
    background: #005fcc;
}